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Why do English builders-Princess/Sunseeker install 2 large zincs right on the hull bottom?

Discussion in 'Props, Shafts & Seals' started by Capt J, Mar 30, 2020.

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  1. bayoubud

    bayoubud Senior Member

    Feb 19, 2017
    Looks right to me. On a fiberglass hull all is connected to the bonding strap including the shaft with a slip ring and the zinc plate. Rudders if not connected have a zinc. Nothing is grounded to the engine, all electrical components have return ground wire to the DC bus or start batteries, less electrolysis. Makes sense not be running DC current thru the engine, dissimilar metals, and seawater components resulting in no pencil zincs maintain, less electrolysis.
    This is a better explanation:
  2. PacBlue

    PacBlue Senior Member

    Jan 9, 2009
    Dana Point, Ca
    That is the missing document , without it the diagram did not add up. What engine model is it for?
  3. mapism

    mapism Senior Member

    Aug 9, 2008
    All of their pre-common rail D28XX engines.

    But in the meantime I got hold also of a much newer installation manual, specifically meant for CR engines.
    I'm not posting the relevant pages because aside from being the Italian version, ...erm... I'm not supposed to have it.
    Anyway, the only relevant difference is a totally new section related to the connections of Rexroth electronic levers and their control units in the e/r.
    The statement which I underlined in my previous post is still exactly the same, language aside.

    Not that I expected any relevant differences, mind: I already knew that the general MAN bonding logic is valid also for CR engines.
    What I was unsure of (and still am) is whether they now ask a specific placement of the external anode bonded to the engine.
    But unless it's hidden in some fine printing which I missed, also the CR engines installation manual does NOT specify that.

    On the other hand, boat builders work jointly with engine manufacturers for anything engine-related on a new model, in order to get their advance approval, also for warranty reasons.
    So, manual aside, I think it remains likely that MAN became more strict in recent years about placing that zinc in a position where it's permanently submerged.
    I will see if I can cross-check this directly with a builder, but it will take me a while.
  4. Hull Diver

    Hull Diver New Member

    Jun 13, 2020
    This has been a great thread so far. Really enjoyed the parts I've read while scanning through trying to find an answer to my question. Its not my intention to hijack this thread or anything but i do have a question peripheral to the topic. Question is

    Are the bolts / all thread on sunseaker hull zincs exposed underneath the batteries.

    While trying to loosen the nuts, the all thread started to turn which is an all stop moment on that maintenance. The captain for whatever reason... Doesnt want to undo the all the batteries without being sure the hull bolts are there.
  5. Capt J

    Capt J Senior Member

    Jul 11, 2005
    Fort Lauderdale
    What size/year Sunseeker? I don't know, BUT in all of the Sunseekers I've dealt with for more than a few days, 52' Manhattan, 62' Predator, 66' Manhattan the batteries are in sealed battery boxes on a shelf above the hull bottom. The bilge is below them and a good 8"+ at that, so you should be able to take a camera phone and take a picture or in the sizes I mentioned above, be able to get your hand on them without removing any batteries. Try calling Nautikos. the dealer in Miami and talking to one of their techs, Angel, he's extremely knowledgable.